Many semiconductor circuits with digital gates require a defined level for setting or resetting the digital gates when the supply voltage is turned on, in order to be able to bring the semiconductor circuits to a defined state. Circuits that detect the operating voltage and supply the defined level are also referred to as power-on-reset, or POR, circuits. For example, when a defined level of the supply voltage is reached, at which the digital elements of the semiconductor circuit can begin to function safely, an output signal of the POR circuit is designed to change its digital level. In many cases, the defined level is emitted in inverted form. The corresponding signals are often referred to as reset and inverted reset signals, respectively.
There already exist various POR circuits, each concentrating on given parameters such as a precise switching threshold, a low power consumption, temperature stability or temporally defined duration of the output signal. In many designs, a bandgap structure is used to achieve a precise switching threshold. To achieve low power consumption, high resistances that can limit the current flow are used in conventional POR circuits. Alternatively, conventional POR circuits have an energy-saving mode that can be actuated from the outside or by self-shutoff. Such POR circuits generally have a large space requirement and/or a still considerable power need when integrated on a semiconductor.